(a) Field of the Invention
This invention relates to hydrostatic motors, pumps and vehicles, which have revolvable members, which are driven thereby. The aim of the invention is to improve especially the motors and vehicles by adding additional arrangements to the motors which may operate independently of the main fluid flow or depending thereon and whereby arrangements are obtained, which over a one-way clutch means or over a free-wheeling arrangement or over an axially moveable member supply specific features or safeties to the respective vehicle. The vehicle itself may be a road vehicle, a waterborne vehicle or an airborne craft. The specific field of the invention deals with a twin rotor helicopter in combination with an inclinable upper structure.
(b) Description of the Prior Art
In road vehicles it has become necessary and is, in some countries, required by law, that the vehicle has a brake on the fluid motors which drive the wheels or tracks. A coupling was, therefore, mounted around the shaft of the motor and supplied with fluid for action against a spring means through the outside of the housing of the motor. The control fluid supply from radially outside through the housing is, however, inconvenient and in addition the entering fluid is prevented or braked from radial inward flow at high speed of the revolving clutch or coupling. The control devices of the known art are therefore, ineffective at high rotary speeds of the motor.
In vertically taking off and landing airborne craft, for example, in helicopters, it was common to switch the propeller blades to autorotation when an emergency landing was required. When, however, the pilot misjudged the situation or acted too late or incorrectly, it could happen that the craft would crash.